摘要
研究基于模型的结构裂纹故障诊断中的正反问题,即求解含裂纹参数结构的固有频率以及利用实测固有频率,定量识别裂纹参数。构造用于求解正问题的一维区间B样条小波裂纹单元,通过求解裂纹结构有限元模型,绘制以裂纹等效刚度与裂纹位置为变量的三阶频响函数解曲线,将实际测出的系统前三阶固有频率作为输入,根据曲线的交点定量预示出裂纹的位置和深度。实验研究表明,文中构造的区间B样条小波裂纹单元有效克服了传统有限元分析在求解裂纹奇异性问题时存在的效率低、精度差甚至难以收敛到正确解的缺陷,同时具有足够的辨识精度。
The model-based forward and inverse problems in the diagnosis of structural crack fault were studied. The forward problem is to solve the natural frequencies through cracked structural model and the inverse problem is to quantitatively determine the crack parameters using the experimentally metrical frequencies. Then, The one- dimension crack element of B-spline wavelet on the interval was built to solve the forward problem. Graphs of crack equivalent stiffness versus crack location were plotted by providing the first three natural frequencies as an input. The intersection of the three curves predicted the crack location and size. The experimental study verified the validity of the crack element in solving crack singular problems to overcome the disadvantages of traditional FEM (finite element method), such as low efficiency, insufficient accuracy, slow convergence to correct solutions etc. At the same time, it had adequate identification precision. The new method can be applied to prognosis and quantitative diagnosis of incipient cracks.
出处
《机械强度》
EI
CAS
CSCD
北大核心
2005年第2期163-167,共5页
Journal of Mechanical Strength
基金
国家自然科学基金重点资助项目(50335030)
高校博士点基金资助项目(20040698026)
西安交通大学自然科学基金资助项目。~~
关键词
区间B样条小波
有限元
梁单元
裂纹单元
定量诊断
B-Spline wavelet on the interval
Finite element method
Beam elements
Crack element
Quantitative diagnosis
